Re: setting background color to drawing area

[Paul Barton-Davis <pbd Op Net>]

In message <14894 45509 293328 823890 helion crl nmsu edu>you write:
>
>    Billy> I've been looking throught the archived mail but havent found
>    Billy> anything but discussions about doing this.  I'm just on my 2nd day
>    Billy> with gtk and need some assistance.
>
>Setting it is easy.  Changing it a lot seems to be trickier.  Anyway:
>
>  GdkColor newbg;
>  GtkStyle *style;
>
>  style = gtk_style_copy(gtk_widget_get_style(widget));
>  style->bg[GTK_STATE_NORMAL] = newbg;
>  gtk_widget_set_style(widget, style);
>
>You have get the color you want by using the GDK color routines first.

just to be persnickety again, doing this directly in the code is a
generally bad idea. instead do this:

   gtk_widget_set_name (area_widget, "MyArea");

then load an RC file with

   style "my_area" {
       bg[NORMAL] = { N1, N2, N3 }
       bg[SELECTED] = { N4, N5, N6 }
   }
   widget "*MyArea" style "my_area"

where N1..N6 are suitable values between 0.0 and 1.0, and define the
RGB levels for the desired colors.

then to change colors:

   gtk_widget_set_state (area_widget, GTK_STATE_SELECTED);

you save yourself typing a bunch of code, and more importantly, the
colors can be changed without recompilation. 

this only works if you have a limited number of colors, of course. if
you really want to change to one of more than about 4 colors, you'll
have to use mark's suggested method, except that you should really be
using the rc_style, as indicated in a message from Havoc:

 GdkColor red = { 0, 65535, 0, 0 };
 GtkRcStyle *rc_style = gtk_rc_style_new ();
 rc_style->bg[GTK_STATE_NORMAL] = red;
 rc_style->color_flags[GTK_STATE_NORMAL] |= GTK_RC_BG;
 gtk_widget_modify_style (widget, rc_style);
 gtk_rc_style_unref (rc_style);

--p